In typical vehicle heating systems, a first air flow is passed through a heat exchanger, heated from the vehicle engine coolant, and this air flow is mixed with a second air flow to provide a temperature-controlled output to the vehicle cabin. The second air flow may be derived directly from outside the vehicle or may be a flow derived from a evaporator of an air conditioning device.
Typically, the first air flow is incident on one side of a mixing chamber and the second flow is incident on the second opposite side of the air mixing chamber.
The disadvantage of this arrangement is that the temperature distribution across the air mixing chamber is uneven due to stratification effects especially where one of the air flows is substantially greater than the other.
It is possible to overcome this problem at least to a certain extent, by the use of baffles. However, baffles have two disadvantages, namely the reduction of air flow volume caused by the baffle and the undesirable noise caused by passage through the baffle.
Accordingly, it is an object of the present invention to provide a mixing device which at least partly overcomes the abovementioned problems.